Rebecca Schaeffer

All nightmares begin as dreams. Ness used to be terrified of Nightmares: people who'd turned into their worst fears while they slept. She's finally free of that terror... but Nightmares aren't the only dangers around. Newham is a city where it's easy to die, but hard to live - and Ness fears her own mortality. So when the monster responsible for creating Nightmares asks Ness for a favor, she agrees - in exchange for him turning her into an indestructible Nightmare of her choice.
When things spiral out of control, Ness finds herself in the crosshairs of enemies old and new - and this time, she can't run from her problems. If she wants to survive, she's going to have to conquer the most difficult enemy of all: herself.